This invention relates generally to anionic polymerization of 1,3-pentadiene (piperylene). The 1,3-pentadiene is generally in admixture with other saturated and unsaturated 5 carbon hydrocarbons. One source of such an admixture is a 5 carbon distillation cut obtained from a cracking of petroleum. This invention also relates to the polymer of 1,3-pentadiene so prepared. This invention further relates to a hydrogenated polymer of 1,3-pentadiene.
It has been found that 1,3-pentadiene does not necessarily polymerize under polymerization conditions where other conjugated dienes, such as isoprene and butadiene, polymerize readily. It has been found that an organic polar compound is required as a co-initiator with a number of known anionic polymerization catalysts in order to produce a discernible amount of polymer within a reasonable time. It has also been found that a pure, or substantially pure, 1,3-pentadiene monomer polymerization feed stream is not essential. In fact, only a few of the components in an impure five carbon atom hydrocarbon fraction need to be neutralized and/or removed prior to polymerization of 1,3-pentadiene from the hydrocarbon fraction.
Accordingly, a primary object is to anionically polymerize 1,3-pentadiene from a mixture of saturated and unsaturated hydrocarbons in a simple and economic manner. A suitable hydrocarbon mixture is a 5 carbon atom fraction obtained from a cracking of petroleum. A related object is to produce saturated synthetic oils by hydrogenating the anionically polymerized 1,3-pentadiene.
Other objects and advantages will appear in the more detailed description and examples set forth below. It is to be understood, however, that the more detailed description and examples are given by way of illustration and explanation only, and not by way of limitation. Various changes to the description and examples may be made by those skilled in the art without departing from the scope and spirit of the present invention.